This happened today and I've never had one before. i recently swapped out the superdrive but it has been operating normally for a week now. Can anyone tell me off the top of their head what this might be a result of? I searched the forums and didn't really see anything that addressed this particular cause. It says "unlocking and unlocked mutex or spinlock". Here's the full report:

Interval Since Last Panic Report: 314360 sec
Panics Since Last Report: 1
Anonymous UUID: 973011D1-936F-4723-B311-8FDAAA3741D7

Fri Mar 12 10:06:17 2010
panic(cpu 0 caller 0x226820): "thread_invoke: preemption_level -1, possible cause: unlocking an unlocked mutex or spinlock"@/SourceCache/xnu/xnu-1486.2.11/osfmk/kern/sched_prim.c:1471
Backtrace (CPU 0), Frame : Return Address (4 potential args on stack)
0x55643e18 : 0x21b2bd (0x5cf868 0x55643e4c 0x223719 0x0)
0x55643e68 : 0x226820 (0x5876cc 0xffffffff 0x587664 0x225ec4)
0x55643ee8 : 0x226f27 (0x7d043f0 0x0 0x55643f48 0x54966b)
0x55643f58 : 0x226f92 (0x22f88a 0x863ea0 0x0 0x2a0596)
0x55643f78 : 0x22fa24 (0x22f88a 0x863ea0 0x0 0x0)
0x55643fc8 : 0x29d68c (0x863ea0 0x0 0x10 0xa7e3ba0)

BSD process name corresponding to current thread: kernel_task

Mac OS version:
10C540

Kernel version:
Darwin Kernel Version 10.2.0: Tue Nov 3 10:37:10 PST 2009; root:xnu-1486.2.11~1/RELEASE_I386
System model name: MacBookPro4,1 (Mac-F42C89C8)

System uptime in nanoseconds: 129361875979477
unloaded kexts:
com.apple.driver.initioFWBridge 2.5.1 (addr 0x5bd1d000, size 0x12288) - last unloaded 111195681550292
loaded kexts:
com.bresink.driver.BRESINKx86Monitoring 5.0
com.vmware.kext.vmnet 2.0.0
com.vmware.kext.vmioplug 2.0.0
com.vmware.kext.vmci 2.0.0
org.pqrs.driver.KeyRemap4MacBook 6.4.0
com.Cycling74.driver.Soundflower 1.5.0
jp.plentycom.driver.SteerMouse 3.9
com.vmware.kext.vmx86 2.0.0
com.apple.filesystems.ntfs 3.1 - last loaded 111115633328076
com.apple.driver.Oxford_Semi 2.5.1
com.apple.filesystems.udf 2.1
com.apple.driver.AppleHWSensor 1.9.2d0
com.apple.driver.AppleUpstreamUserClient 3.1.0
com.apple.driver.AppleIntelPenrynProfile 17
com.apple.Dont_Steal_Mac_OS_X 7.0.0
com.apple.GeForce 6.0.6
com.apple.driver.AudioIPCDriver 1.1.2
com.apple.driver.AppleHDA 1.7.9a4
com.apple.driver.AppleBacklight 170.0.14
com.apple.driver.SMCMotionSensor 3.0.0d4
com.apple.iokit.AppleYukon2 3.1.14b1
com.apple.driver.ACPI_SMC_PlatformPlugin 4.0.1d0
com.apple.driver.AppleLPC 1.4.9
com.apple.driver.AirPortBrcm43xx 421.91.26
com.apple.kext.AppleSMCLMU 1.4.5d1
com.apple.filesystems.autofs 2.1.0
com.apple.driver.AppleUSBTCButtons 1.8.0b4
com.apple.driver.AppleUSBTCKeyboard 1.8.0b4
com.apple.driver.AppleIRController 251.1.4
com.apple.driver.MaxTranserSizeOverrideDriver 2.5.1
com.apple.iokit.SCSITaskUserClient 2.6.0
com.apple.driver.AppleUSBHub 3.8.4
com.apple.iokit.IOAHCIBlockStorage 1.6.0
com.apple.BootCache 31
com.apple.AppleFSCompression.AppleFSCompressionTyp eZlib 1.0.0d1
com.apple.driver.AppleUSBEHCI 3.7.5
com.apple.driver.AppleAHCIPort 2.0.1
com.apple.driver.AppleIntelPIIXATA 2.5.0
com.apple.driver.AppleFWOHCI 4.4.0
com.apple.driver.AppleEFINVRAM 1.3.0
com.apple.driver.AppleUSBUHCI 3.7.5
com.apple.driver.AppleRTC 1.3
com.apple.driver.AppleHPET 1.4
com.apple.driver.AppleSmartBatteryManager 160.0.0
com.apple.driver.AppleACPIButtons 1.3
com.apple.driver.AppleSMBIOS 1.4
com.apple.driver.AppleACPIEC 1.3
com.apple.driver.AppleAPIC 1.4
com.apple.security.sandbox 0
com.apple.security.quarantine 0
com.apple.nke.applicationfirewall 2.1.11
com.apple.driver.AppleIntelCPUPowerManagementClien t 96.0.0
com.apple.driver.AppleIntelCPUPowerManagement 96.0.0
com.apple.iokit.IOFireWireSerialBusProtocolTranspo rt 2.0.0
com.apple.iokit.IOFireWireSBP2 4.0.5
com.apple.driver.AppleBluetoothHIDMouse 1.4.0d7
com.apple.driver.IOBluetoothHIDDriver 2.2.4f3
com.apple.driver.AppleProfileReadCounterAction 17
com.apple.driver.AppleProfileTimestampAction 10
com.apple.driver.AppleProfileThreadInfoAction 14
com.apple.driver.AppleProfileRegisterStateAction 10
com.apple.driver.AppleProfileKEventAction 10
com.apple.driver.AppleProfileCallstackAction 20
com.apple.iokit.IOSurface 73.0
com.apple.iokit.IOBluetoothSerialManager 2.2.4f3
com.apple.iokit.IOSerialFamily 10.0.3
com.apple.driver.DspFuncLib 1.7.9a4
com.apple.iokit.IOAudioFamily 1.7.2fc1
com.apple.kext.OSvKernDSPLib 1.3
com.apple.nvidia.nv50hal 6.0.6
com.apple.NVDAResman 6.0.6
com.apple.iokit.IONDRVSupport 2.0
com.apple.iokit.IOFireWireIP 2.0.3
com.apple.iokit.AppleProfileFamily 41
com.apple.driver.AppleHDAController 1.7.9a4
com.apple.iokit.IOHDAFamily 1.7.9a4
com.apple.driver.IOPlatformPluginFamily 4.0.1d0
com.apple.iokit.IO80211Family 310.6
com.apple.iokit.IONetworkingFamily 1.9
com.apple.iokit.IOGraphicsFamily 2.0
com.apple.driver.AppleSMC 3.0.1d2
com.apple.driver.AppleHIDMouse 1.4.0d7
com.apple.driver.AppleUSBMultitouch 204.9
com.apple.driver.BroadcomUSBBluetoothHCIController 2.2.4f3
com.apple.driver.AppleUSBBluetoothHCIController 2.2.4f3
com.apple.iokit.IOBluetoothFamily 2.2.4f3
com.apple.iokit.IOUSBHIDDriver 3.8.4
com.apple.iokit.IOSCSIBlockCommandsDevice 2.6.0
com.apple.iokit.IOUSBMassStorageClass 2.5.1
com.apple.driver.AppleUSBMergeNub 3.8.5
com.apple.driver.AppleUSBComposite 3.7.5
com.apple.iokit.IOSCSIMultimediaCommandsDevice 2.6.0
com.apple.iokit.IOBDStorageFamily 1.6
com.apple.iokit.IODVDStorageFamily 1.6
com.apple.iokit.IOCDStorageFamily 1.6
com.apple.driver.XsanFilter 402.1
com.apple.iokit.IOATAPIProtocolTransport 2.5.0
com.apple.iokit.IOSCSIArchitectureModelFamily 2.6.0
com.apple.iokit.IOUSBUserClient 3.8.5
com.apple.iokit.IOAHCIFamily 2.0.2
com.apple.iokit.IOATAFamily 2.5.0
com.apple.iokit.IOFireWireFamily 4.1.7
com.apple.iokit.IOUSBFamily 3.8.5
com.apple.driver.AppleEFIRuntime 1.3.0
com.apple.iokit.IOHIDFamily 1.6.1
com.apple.iokit.IOSMBusFamily 1.1
com.apple.security.TMSafetyNet 6
com.apple.kext.AppleMatch 1.0.0d1
com.apple.driver.DiskImages 281
com.apple.iokit.IOStorageFamily 1.6
com.apple.driver.AppleACPIPlatform 1.3
com.apple.iokit.IOPCIFamily 2.6
com.apple.iokit.IOACPIFamily 1.3.0
Model: MacBookPro4,1, BootROM MBP41.00C1.B03, 2 processors, Intel Core 2 Duo, 2.4 GHz, 4 GB, SMC 1.27f2
Graphics: NVIDIA GeForce 8600M GT, GeForce 8600M GT, PCIe, 256 MB
Memory Module: global_name
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0x8C), Broadcom BCM43xx 1.0 (5.10.91.26)
Bluetooth: Version 2.2.4f3, 2 service, 1 devices, 1 incoming serial ports
Network Service: AirPort, AirPort, en1
Serial ATA Device: ST9500325AS, 465.76 GB
Parallel ATA Device: HL-DT-ST DVDRW GSA-S10N, 6.01 GB
USB Device: USB Storage, 0x05e3 (Genesys Logic, Inc.), 0x0715, 0xfa300000
USB Device: Built-in iSight, 0x05ac (Apple Inc.), 0x8502, 0xfd400000
USB Device: BRCM2046 Hub, 0x0a5c (Broadcom Corp.), 0x4500, 0x1a100000
USB Device: Bluetooth USB Host Controller, 0x05ac (Apple Inc.), 0x820f, 0x1a110000
USB Device: Apple Internal Keyboard / Trackpad, 0x05ac (Apple Inc.), 0x0230, 0x5d200000
USB Device: IR Receiver, 0x05ac (Apple Inc.), 0x8242, 0x5d100000
FireWire Device: HDD, Iomega, Up to 800 Mb/sec